Hunting Antarctic Meteorites

University of Arizona News Release

2005 November 10

Not many people celebrate their year-end holidays on the east Antarctic ice
sheet. But nearly every year for more than a decade, University of Arizona
Lunar and Planetary Laboratory (LPL) professors, graduate students or alumni
have.

They have been part of the Antarctic Search for Meteorites (ANSMET) program,
intent on collecting pieces of asteroids, the moon and Mars which have landed as
meteorites on the whitest place on Earth.

"ANSMET is such an amazing program," UA postdoctoral researcher Jani Radebaugh
says. "It's like getting free samples from outer space, free except for the cost
of traveling to Antarctica to collect them."

Radebaugh is among 15 scientists and mountaineers selected for the 2005-2006
NSMET program. So is Gordon Osinski, a recent LPL postdoctoral researcher now
with the Canadian Space Agency. The 20-year-old ANSMET program is funded by the
National Science Foundation Office of Polar Programs and by NASA's Solar System
Exploration Division. Planetary scientist Ralph Harvey of Case Western Reserve
University heads the collecting expeditions.

"The program is a wonderful thing, because now there's a push to go back to the
moon and Mars and return samples to try to understand these bodies," Radebaugh
said. "We can learn a lot more about these bodies as we increase the collection
of the samples that land on Earth. I think these expeditions are a really
important service to planetary science."

Radebaugh, who earned her UA doctorate last May, will join the Brigham Young
University geology faculty this fall. "I think this experience would be fun for
students to hear about," she added.

Postodoctoral researcher Julia Goreva was on the successful 2004-2005 meteorite
collecting expedition. She and 11 others collected 1,230 meteorites. Among these
were more than 300 pounds of "pallasite" meteorites -- rare rocks originally from
the core-mantle boundary of a small destroyed planet or a large asteroid. One
pallasite, the largest yet found, weighed 70 pounds.

"For the past 10 years I've been studying meteorites -- destroying them,
dissolving them, melting, burning, getting every bit of information they can
give me about the processes that took place at times when the Earth was just an
embryo," Goreva said. "ANSMET is a program that builds a collection available to
any scientist around the globe, so it was very important for me to become one of
the people who can personally contribute to the pool of rocks that continue to
puzzle me in the lab."

Radebaugh leaves for New Zealand on Nov. 17. Expedition members get completely
outfitted at Christchurch, N.Z., then board an LC 130 cargo airplane for an 8-hour
flight to McMurdo Station, Antarctica. Bad weather can mean turning around
mid-flight and returning to Christchurch. It took one expedition four tries to
reach McMurdo.

After survival and other training at McMurdo, Radebaugh, Osinski and their
colleagues will head for the Antarctic plateau inland of the Miller Range in the
Transantarctic Mountains and set up base camp. They'll live in 2-person tents
for five weeks during the South Polar summer, when temperatures hover around
minus 30 degrees Fahrenheit.

Goreva said, "I never thought that two girls could eat a pound of butter per
week and a pound of bacon for breakfast. That does keep you warm!"

Antarctica is by far the best place on Earth to search for meteorites, mainly
for two reasons, Ralph Harvey explains on the ANSMET Website,
http://geology.cwru.edu/~ansmet/.
One is that although meteorites fall randomly all over the globe, they are more
easily found against Antarctica's plain, bright ice than on other Earth
surfaces. The other has to do with the fact that as snow accumulates on the
continental ice sheet, the weight pushes the ice sheet toward the edges of the
continent.

"As this big, very thick ice sheet slowly spreads out, it moves like a conveyor
belt and delivers meteorites to the bases of mountains," Radebaugh said.

Over tens of thousands of years, phenomenal concentrations of meteorites can
develop, as high as one meteorite per square meter in some places, Harvey says
on the ANSMET Website. The ANSMET program archives all its meteorites at NASA's
Johnson Space Center in Houston.

That many LPL researchers have been on the Antarctica meteorite-collecting
teams shows "just how involved the LPL is in the planetary science community,"
Radebaugh said. "The lab has a big group of people doing different kinds of
research. The UA is a strong institution in planetary science. And, I also think
many of us became involved because we have so many friends who have gone, and
they know how exciting it is, how much fun."

"Antarctica is the most amazing place I've seen in my life," Goreva said. "At
times it was breathtakingly beautiful, at times harsh and angry, but always
pure, and it made me feel, well, very small. It was an overwhelming feeling to
realize that you are the first person to be in that particular place in the
world. (Goreva was on the 4-person reconnaissance team, the advance group for
the 8-person collecting team, last season.) Except for the four of us, there was
not a single living being hundreds of miles around."

Goreva added, "One of the first questions people ask is if spending two months
on the ice was worth it. The short answer is -- every second of it. Would I do
it again? In a heartbeat."

Lunar and Planetary Lab scientists who have been on ANSMET expeditions include:

Julia Goreva, postdoctoral researcher (2004-2005)

Nancy Chabot, graduate student (1998-1999), then as an alumna and ANSMET
program assistant (2001-2002 through 2004-2005)